email verification re-send function with double opt in registration

I have adopted the 'Double opt in registration' system for my application system which I am fine with apart from one part which is the 'Re-send email verification feature.

In the 'Add URL resend function' section, part 42. it asks to paste in the following code in the 'email-verified column' in the 'bindings tab', of the 'update record behaviour'

<?php echo(($row_SecurityAssistusers['UserEmail'] != $_POST["User_Update_group_Email"])? '0': $row_SecurityAssistusers['emailVerified']); ?>

I understand I have to adapt this to refer to my recordsets and databases so they are the correct bindings, apart from the section that reads - $_POST["User_Update_group_Email"])? '0':

I am unsure what this is referring to or how to adopt it for when I create the 'Update record behaviour'. Im assuming it is binding a form field value.. but from where?

I have attached all relevant files if it helps. Plus screen shots of Tutorial Section and Database.

Pages Reference:
Success Page - email-confirm.php
Registration page - add-rtm-account.php
Registration email - Blank_4.php
Confirm Page - account-verified.php
Re-send email - Blank_5.php
user update - user-update.php

I hope this makes sense.

Thanks in advance

That line of code is simply telling the database to reset the verified field back to '0' if someone updates their email address.

So if the entered email address doesn't match the email address already in the database, set the email verified column to 0, otherwise if the email address hasn't changed, leave the verified value what it already was before the update.